Attorneys General from 45 states around the country called on the major phone companies today to provide their customers with effective tools to help stop the flood of unwanted robocalls. The effort comes just weeks after the Federal Communications Commission made clear that phone companies can and should offer such tools and as nearly 330,000 Americans have joined Consumers Union’s End Robocalls campaign calling on them to do so.

“Robocalls ring day and night and too often target vulnerable consumers with costly rip-offs,” said Tim Marvin, manager of Consumers Union’s End Robocalls campaign. “State law enforcement officials, federal regulators, and the public all agree — the phone companies need to do more to stop robocalls before they invade our homes. Phone carriers are in the best position to provide their customers with relief and it’s time for them to act.”

In a letter sent to AT&T, Sprint, Verizon, T-Mobile and CenturyLink, 45 state attorneys general noted that they have received numerous consumer complaints about robocalls and urged the phone companies to “act without delay” to offer call-blocking technologies to their customers. The letter notes that law enforcement alone cannot stop unwanted robocalls and that “[t]he better solution is to stop intrusive calls before they ever reach the consumer.”

Robocalls are unsolicited pre-recorded or live phone calls made using a computerized auto-dialer. Americans have registered more than 217 million phone numbers on the Federal Trade Commission’s “Do Not Call” list, yet robocalls are rampant. Last year, the Federal Trade Commission received 3 million complaints from the public about unwanted calls, many from scammers or illegitimate companies that flagrantly violate the law. Telephone scams cost consumers an estimated $350 million in financial losses in 2011.

Technology is already available to stop robocalls before they reach a consumer’s landline or wireless phone, but the phone companies have resisted making them widely available to their customers.